en fr What is the relevant level of detail to model the growth of a mixed forest Comparison of a model family and application to mixed stands of sessile oak and Scots pine Quel est le niveau de détail pertinent pour modéliser l

en fr What is the relevant level of detail to model the growth of a mixed forest Comparison of a model family and application to mixed stands of sessile oak and Scots pine Quel est le niveau de détail pertinent pour modéliser l - Download this document for free, or read online. Document in PDF available to download.

1 UR EFNO - Ecosystèmes forestiers

Abstract : Appropriate tools and models are needed for the management of mixed forests. The aim of this thesis is to show how the construction and the comparison of models with different levels of detail can help us to choose the most appropriate level to model the growth of a mixed stand. We developed a family of models at different levels of detail from data collected in mixed stands of sessile oak Quercus petraea L. and Scots pine Pinus sylvestris L. : a tree distance independent model MAID, a tree distance dependent model MADD, three stand models and an intermediate model bridging the MAID and the MADD. We ensured consistency between models using several approaches in order to make relevant comparisons. These models have given us some knowledge on the growth and dynamics of these forests, in particular on the spatial and temporal interactions between oaks and pines. Thus, we showed a compensatory growth phenomenon between the two species using the MAID. The MADD made it possible to show that, in these stands, the intraspecific competition was stronger than interspecific competition. A stand model developed from the MADD helped us to study the influence of mixing rate on production. To assess the quality of models predictions, we used an independent data set obtained by splitting our data. For example, we have shown that the MAID was more efficient than the MADD to predict individual increments. The models were also compared on examples of applications with short or medium term simulations. The proposed approach is of interest for both understanding the studied phenomenon and developing predictive tools. The different results of this work, allowed us to assess the relevance of a type of model for different contexts of use. This very general approach could be applied to the modeling of other processes such as mortality or regeneration.

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